NIPISSING BLUE WALLEYE

Description: Most evidence, including genetic tests, suggests that the
Lake Nipissing blue walleye is a colour morph of the yellow walleye
(Sander vitreus). However, even W.B.Scott and E.J. Crossman, two of the
foremost authorities on freshwater fishes in North America, state that
the grey-blue walleyes seen regularly in Lake Nipissing cannot be denied
nor proven to be blue walleyes based on their observations.

Grey-colored walleyes, which are the result of bluish color mucus, occur
with varying frequency in most yellow walleye populations. Individuals
of a slightly bluer color occur in Lake Nipissing. The known blue
walleyes of Lake Erie & Ontario were distinguishable from most grey-blue
forms, in that they were more slate-blue or steel-blue on the dorsal
surface, ice-blue to silvery on the sides and silvery to white on the
ventral surface. The pelvic fins were white. In the mid 1900s, the blue
walleyes of Lake Nipissing were distinctive enough from yellows in the
lake to have different fishing catch limits (An angler could catch 35
blue walleye in one day, but only 6 yellow walleye per day).

At the turn of the century (1900), the walleye of Lake Nipissing were
almost all blue in color. However, this stock was fished until depleted
by a commercial gill net fishery started after World War I to provide
food and employment after the war. Once this fishery was closed, efforts
turned to replenishing the stock, and a faster-growing yellow strain of
walleye from southern Ontario was introduced into the lake. This new
yellow strain apparently naturalized in the lake, becoming a
self-sustaining population. The yellow walleye and the blue walleye can
and did interbreed, likely rendering whatever pure blue stock existed in
Lake Nipissing very rare and possibly extinct. To date, all genetic
tests of Lake Nipissing blue walleyes indicate their shared ancestry
with yellow walleye in the lake. However, every year a few very distinct
blue-colored walleye are caught in Lake Nipissing, which keeps alive the
mystery of whether or not true blue walleye still exist.